Use the else statement to specify a block of code to be executed if the condition is False.
if (condition)
{
// block of code to be executed if the condition is True
}
else
{
// block of code to be executed if the condition is False
}
int time = 20;
if (time < 18)
{
Console.WriteLine("Good day.");
}
else
{
Console.WriteLine("Good evening.");
}
// Outputs "Good evening."
C# supports the usual logical conditions from mathematics:
You can use these conditions to perform different actions for different decisions.
C# has the following conditional statements:
if to specify a block of code to be executed, if a specified condition is trueelse to specify a block of code to be executed, if the same condition is falseelse if to specify a new condition to test, if the first condition is falseswitch to specify many alternative blocks of code to be executedVery often, in programming, you will need a data type that can only have one of two values, like:
For this, C# has a bool data type, which can take the values true or false.
Because strings must be written within quotes, C# will misunderstand this string, and generate an error:
string txt = "We are the so-called "Vikings" from the north.";
The solution to avoid this problem, is to use the backslash escape character.
The backslash (\) escape character turns special characters into string characters: Continue reading C# Special Characters
You can access the characters in a string by referring to its index number inside square brackets [].
This example prints the first character in myString:
string myString = "Hello"; Console.WriteLine(myString[0]); // Outputs "H"
Note: String indexes start with 0: [0] is the first character. [1] is the second character, etc.
Another option of string concatenation, is string interpolation, which substitutes values of variables into placeholders in a string. Note that you do not have to worry about spaces, like with concatenation : Continue reading C# String Interpolation
The + operator can be used between strings to combine them. This is called concatenation:
string firstName = "John "; string lastName = "Doe"; string name = firstName + lastName; Console.WriteLine(name);
Note that we have added a space after “John” to create a space between firstName and lastName on print.
Strings are used for storing text.
A string variable contains a collection of characters surrounded by double quotes:
Create a variable of type string and assign it a value:
string greeting = "Hello";
The C# Math class has many methods that allows you to perform mathematical tasks on numbers
The Math.Max(x,y) method can be used to find the highest value of x and y:
As with comparison operators, you can also test for True or False values with logical operators.
Logical operators are used to determine the logic between variables or values:
| Operator | Name | Description | Example | Try it |
|---|---|---|---|---|
| && | Logical and | Returns True if both statements are true | x < 5 && x < 10 | |
| || | Logical or | Returns True if one of the statements is true | x < 5 || x < 4 | |
| ! | Logical not | Reverse the result, returns False if the result is true | !(x < 5 && x < 10) |